A main trend in modern dairy farm industry is an increased degree of automation. For instance, machine milking may be performed by automatic milking machines in a completely automated manner. Further, fully automated animal managing systems may take care of milking, feeding, milk inspection, milk sampling, animal traffic, etc. in an area wherein the dairy animals are walking about freely and are visiting the milking machines on a voluntary basis.
An automated milking machine involves large costs and has a limited milk production capacity. Thus, in order to obtain a high utilization of the automated milking machine, which animals are visiting on a voluntary basis, it should be operated as frequently as possibly, most preferably continuously during day and night. Further, animals having a high milk production should be milked more often than animals having a low milk production. The operation and use of an automated milking machine in order to obtain an optimal milk production is an arduous task. Naturally, ethical aspects as well as animal care have to be considered.
EP 0 332 230 A2 (VAN DER LELY) discloses a method of automatically milking animals, which are allowed to visit individually a milking parlor comprising a milking robot and an animal identification system. The milking animals make a more or less regular appearance in the milking parlor, and can be lured to the milking parlor by the presence of concentrate or by calling the animals by means of sound signals. To this end each animal has a collar with a receiver attached thereto, which is connected to a loudspeaker located in the region of the animal's ears. By means of sending a call signal with agreeable sounds each desired animal can be invited to go to the milking parlor, while other animals can be hindered to go the milking parlor by means of an unpleasant signal.
While such methods include enticing animals to the milking parlor, they do not suggest when to entice the animals. Animal selective enticing means are often used to entice particular animals, i.e. animals having a large milk production or animals, which have not been milked for a long time, to present themselves at the milking machine.